Fears the man had possible links to terrorism were also being investigated after the man was heard screaming “Allahu Akbar” by police and up to 30 witnesses.
"While this information will be factored into the investigation we are not ruling out any motivations at this stage, whether they be political or criminal," said Queensland Police Service Deputy Commissioner Steve Gollschewski.
"We're working closely with our partner agencies to make sure if there is any indication that it has an extremist slant, or this person had been radicalised, we can discover that.
"Investigators will also consider whether mental health or drug misuse factors are involved in this incident."
After being taken into custody, Ayad who is a former kickboxing champion, continued to show aggression, and allegedly attacked officers as they restrained him.
"Everybody has told us he was completely crazy, they couldn’t recognise him," a French tourist told The Australian.
"He said he wants to kill everybody … maybe there is alcohol and drugs involved."
Tributes have been pouring in for the 21-year-old from across the globe.
Former boyfriend Jamison Stead took to Instagram to share photos of the pair, writing “Rest In Peace Mia. Thank you for the memories."
While her step father, Stewart Cormack, fought back tears in an interview on British TV according to ABC.
"Mia was a rare person who saw beyond race, creed and belief. She would always treat others with dignity, respect and kindness," he said.
"Just seeing her outward appearance could not give you an inkling of how wonderful she was emotionally, socially and mentally. As a peaceful person Mia had huge respect for everybody."